Energy Labeling & Energy Billing Analysis

Discussions of building labels worldwide have pointed out the difference between “asset value” labels, which are based on how a building performs under standard operating conditions, and “operational value” labels, which are based on measurements of energy consumption using the operating conditions that exist at a particular time. Most products, such as cars or appliances, are rated using asset value labels with a standardized operational component— for example, cars are rated by EPA miles per gallon (mpg) but are not resold based on the mpg that the seller actually obtained. But for buildings, analysts generally recognize that both results are useful.
At this summer’s Westford Symposium, l made a presentation entitled “Energy Star- Qualified Homes Stuff.” About one-third of the presentation was dedicated to discrediting the HERS index, which is, at present, an asset value rating (although RESNET is in the process of adding an operational component).
Much of the presentation was based on a checklist prepared by EPA to evaluate the differences between the HERS index and EPA’s Home Energy Yardstick (see Figure 1). The checklist found the EPA Yardstick acceptable and the HERS index unacceptable in every single ...